Mr. Mistry took the helm of the group in December 2012

The board of one of India’s largest conglomerates, Tata Group, surprised investors and analysts Monday by ousting its Chairman Cyrus Mistry, saying it was acting “for the long-term interest” of the company.

Mr. Mistry took the helm of the group, which has 29 listed companies and collective revenue of $100 billion, in December 2012 after Ratan Tata retired.

Three companies–Tata Consultancy Services, Tata Motors and Tata Steel–account for the bulk of the group’s revenue and profit. The performance of the rest of the nearly 100 companies that make up the group varies widely, but the combined revenue of the top three firms makes up 75% of group’s total.

Since Mr. Mistry became chairman, net profit at TCS, the jewel in the crown of Tata Group, has soared. It jumped about 75% between March 2013 and March 2016, while its revenue has grown 72%.

Its stock price has also given better returns compared to other two group stocks during the period, rising 60%. However, this year the stock hasn’t been performing well as its major clients in the U.S. and Europe have cut down discretionary spending.

Tata Motors delivers the highest revenue of the Tata Group stocks thanks to its Jaguar Land Rover luxury car brand. However, its profit growth hasn’t kept pace with its revenue growth in the past four years. Weak performance at its Indian operations and volatile sales of Jaguar Land Rover in China — its single largest market — has hurt its profit.

Its revenue has grown 46% between fiscal 2013 and fiscal 2016, while the net profit is up just 11.4% during the period.

However Tata Steel is worst performer of the three large Tata Group stocks, dragged down by its operations in the U.K. The company is trying to sell its steel mills in the U.K. as sharp fall in global commodity prices and cheap Chinese imports have affected the company’s operations there.

Brokerage CLSA said in a research note that the removal of Cyrus Mistry as chairman of Tata Group will likely impact Tata Steel shares in the near term, while other group stocks are will likely see negligible impact.

It is widely believed that Mr. Mistry was the driver of Tata Steel’s strategy to sell off its European assets. But, this development might raise questions over the continuation of this strategy, CLSA says.